Many broadcasters are delivering television signals to clients containing not only the television program that is viewed by the client in essentially real time, but additional digital information embedded in the television signal. The additional digital information has been termed in the art as “television enhancements.” Television enhancements can be of many forms, including news, web-site links, interactive games, and others. A client's receiver, which could be a television set, a set-top box, and a computer-based system, can simultaneously display the television program as an object window and the television enhancement as another object window.
Typically, the television enhancement transmitted is associated with the television program being simultaneously transmitted. For instance, if the television program is a commercial for a particular product, the enhancement may include one or more web-site links providing information about the product and its manufacturer. If interested, a client can activate the web-site link shown as an object window on the client's display to open a web-site providing further information about the product. Alternatively, for example, the enhancement may include an interactive game which allows a client to receive discounts on the product or actually win the product as a prize. The above are merely examples.
Recently, a cross-industry group named Advanced Television Enhancement Forum (ATVEF) was formed to specify a standard for delivering television enhancements to client receivers. Because the Internet is now widely accepted for the transmission of digital data, the ATVEF specification uses existing Internet standards for the transmissions. For instance, information conforming to the Hypertext Markup Language (HTML) can be transmitted as an enhancement along with the television program signal, and processed by the client receiver to simultaneous display of the television program and the website as separate object windows. The transmission of television enhanced signals can be through a terrestrial wireless medium, cable, satellite system, fiber optics, to name a few.
According to the ATVEF standard, there are three (3) basic data structures for transmission of enhanced television signals: announcements, content, and triggers. Announcements are used to announce currently available programming to client receivers. Typically, announcements are broadcast on a single multicast address that inform client receivers of the multicast address and port number of a particular content for access purposes. The content can be television programs, television enhancements, and triggers. They are typically broadcast from a multi-cast address and port, and can be “tuned” to by a client receiver for reception and real-time display. Triggers identify a Uniform Resource Locator (URL) and a limited human readable string to use in an announcement. When a client receiver receives a trigger, it displays the corresponding URL in the form of a link on the client display to allow the user the opportunity to access the corresponding website if so desired.
Also according to the ATVEF standard, there are two types of transport platforms for transmission of television enhancements: transport “A” and transport “B.” Transport A is for the delivery of triggers only by a forward path and the pulling of data by a required return path. Accordingly, transport “A” is particularly suited for enhanced television that runs on relatively low bandwidth communications medium. Transport B is for delivery of triggers and data by a forward path where the return path is optional. Transport B is typically for true broadcast of both resource data and triggers. The return path can be optionally provided to provide users at their respective client receivers the capability of e-commerce and general web browsing. The invention herein concerns a transport B platform.
The existing announcement provided by the ATVEF has several limitations. First, an announcement for a particular video program is transmitted to clients immediately before the video program is transmitted. There is no provision for announcing available future programs and/or enhancements so that a client receiver can set itself out to receive it at the appropriate time. Second, because of the limited size of the announcement (i.e. 1 Kbyte) and other information which the announcement is required to include, a limited amount of information about the television program can be provided. Typically, just the title of the program is provided. Third, the announcement identifies one (1) program and includes a Universally Unique Identifier (UUID) to identify the corresponding television program.